1. Field of the Invention
The present invention relates to a semiconductor laser apparatus including an active region that emits light having a predetermined wavelength as a semiconductor light-emitting device.
2. Related Background Art
A laser diode that is a semiconductor light-emitting element has a light-emitting active region between a first end surface and a second end surface facing each other. A partial reflection film is formed on the first surface side, while a total reflection film is formed on the first end surface side. A laser resonator is constituted between these partial and total reflection films. Namely, the light emitted in the active region is totally reflected at the total reflection film, and partially reflected at the partial reflection film. The emitted light goes and returns in the laser resonator constructed by these partial and total reflection films, and at this time an induction emission is produced. Thus, a laser oscillation of the laser diode is carried out. Then, part of the light reached from the active region to the partial reflection film is reflected by the partial reflection film, while the remainder transmits the partial reflection film. The light transmitted in the partial reflection film serves as an output laser beam.
Since such a laser beam outputted from the laser diode has a large spread angle, it cannot be immediately applied to a variety of purposes. For this reason, as disclosed in Japanese Patent No.3071360, an optical element such as a lens or an optical path conversion element is used together with the laser diode to collimate the laser beam outputted from the laser diode. Thus, in the semiconductor laser apparatus including the foregoing laser diode and optical element, the laser beam outputted from the laser diode may have a small spread angle due to an operation of the optical element such as a lens and an optical path conversion element even if the emission light originally has a large spread angle.